This invention relates to a method and an apparatus for manufacturing inorganic fiber mats usable as heat insulating materials through a process of forming short fibers of glass.
The conventional methods of forming glass fiber include a pendent take-up method, a pendent blow-off method, a centrifugal method, etc. By such conventional methods, however, the formed fibers have a thin, long shape requiring complex and difficult processes. Besides, as described in the copending U.S. patent application Ser. No. 749,693, such conventional methods bring about undesirable environment for manufacturing work, a public nuisance, increase in labor cost and so on. Such shortcomings of the conventional methods thus have hitherto presented various problems.
Particularly, in the cases of methods disclosed in U.S. Pat. Nos. 2,729,027 and 2,729,030 (Games Slayter et al.) and also in U.S. Pat. No. 2,736,676 (P. J. Frickert), these methods relate to processes of forming continuous long fibers into strand mats. In such a method, a pair of rubber rollers of narrow width are used to squeeze continuous filament strands and to forward them while evenly spreading them on a conveyer of desired width for forming them into a mat-like shape. In accordance with such a conventional method, the melted glass is extruded in a bundle of hundreds of filaments from a nozzle plate. These rollers are arranged to securely catch the bundle of continuous filaments and to pull them downward. This entangles them and brings them into contact with each other. Therefore, to prevent the continuous glass filaments from being broken or crashed during such a process, there is provided a rubber cushion. The products manufactured in this manner have a great specific gravity and excels in strength and are employed as a reinforcement material for the purposes of heat insulation or sound absorption and in FRP and FRC.